Math, asked by ajinkya142, 1 year ago

which term of an A.P is 70, if the first term is 120 and the common difference is -5

Answers

Answered by Krais
18

✨Answer:

11 term is 70.


✨ Step-by-step explanation:

Let 70 be Tn.

Then,

➡️ Tn = a + (n - 1)d

➡️ 70 = 120 + (n - 1) - 5

➡️ 70 = 120 - 5n + 5

➡️ 65 = 120 - 5n

➡️ 5n = 120 - 65

➡️ 5n = 55

➡️ n = 11

70 is the 11 th term of given ap in which first term a is 120 and common difference d is - 5.


Answered by raziahmadmjg
6
let, nth term of AP is 70.

Also, a=120

d=-5

we know thay,

n \: th \: trem \: of \: ap = a + (n - 1)d \\  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  70= 120 + (n - 1) - 5 \\  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \: \:  \:  \:  \:  \: 70 = 120 - 5n + 5 \\  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \: 70 = 125 - 5n \\  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \: 5n = 125 - 70 \\  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \: 5n = 55 \\  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \: n =  \frac{55}{5}  \\  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \: n = 11 \\  \\ hence \: 11th \: term \: will \: be \: 70.

I hope this helps you.
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